Fluid transmission devices



March 19, 1968 H. M. GEYER 3,373,696

FLUID TRANSMI SSION DEVICES March 19, 196s H. M. GEYER. 3,373,696

Filed May 12, 1965 2 Sheets-Sheet 2 United States Patent O 3,373,696 FLUID TRANSMISSHGN DEVICES Howard Marion Geyer, Dayton, Ohio, assignor to General Electric Company, a corporation of New York Filed May 12, 1965, Ser. No. 455,246 6 Claims. (Cl. 10S- 162) The present invention relates to improvements in uid transmission devices of the type which may be employed as either a pump or a motor.

More specically the environment of the invention is found in such a device which comprises a pump body and a plurality of pistons reciprocable in chambers formed therein. The ends of the pistons are so connected to a member which nutates or is otherwise moved relative to the piston body so that the pistons reciprocate within the pump body. The pistons may be reciprocated to pressurize fluid when the device is used as a pump or pressurized iluid may be employed to reciprocate the pistons when the device is used as a motor. In either event fluid inlet and outlet passageways are brought into communication successively with the reciprocating pistons. In the present specification reference will be made primarily to a pump environment, but it is to be understood that at least the broader aspects of the invention will be equally applicable to a motor, as will be apparent to those skilled in the art.

One of the limitations of devices of the type referred to is that high stress concentrations are encountered in transmitting thrust forces between the piston and the nutating means which controls piston reciprocation. These high stress concentrations can cause excessive wear, not only because of high bearing loads, but also as a result of the fact that the lubrication film normally provided is scraped away and rendered ineffective.

The objects of the present invention are to provide a simple and economically manufactured device of the type referred to and in so doing to minimize, if not eliminate, the stress concentrations discussed above and further to actually minimize thrust forces which further contribute to excessive wear conditions.

The above ends are attained by the provision of a pump or the like comprising a pump body having a plurality of chambers formed therein generally parallel to each other and circularly arranged. Pistons are respectively reciprocable in these chambers and project outwardly therefrom. Inlet and outlet passageways respectively communicate with opposite ends of these chambers successively as the pistons rotate. Caps are socketed to receive ball ends formed on the outer ends of the pistons. The caps have iianges disposed in a common plane coincident with the center about which the ball end is generated. A plate is relieved to receive the outer ends of the caps encompassing the ball ends being the flanges so that the anges may engage a bearing surface on the plate also lying on this common plane. Means are provided for nutating the plate relative to the pump body to control and impart reciprocation to the pistons. With the described relationships there is no force transmitted from the pistons to the caps which would cause the caps to tilt relative to the plate, and therefore there is at surface contact therebetween and a minimum unit bearing load which facilitates lubrication.

Further features of the invention are found in the provision of a cam plate having a bearing surface opposed to the pistons projecting from the pump body. The cam plate and pump body are relatively rotatable and the piston chambers are disposed generally parallel to and concentric of the axis of relative rotation. The bearing surface on the cam plate is disposed at an angle to a plane normal to the axis of relative rotation. The nutating plate has opposed surfaces which are preferably parallel. One of these opposed surfaces bears against the angled surface of the cam plate and the other bears against the flanges of the caps. The nutating plate is preferably provided with through holes to receive the outer ends of the caps, which holes are sealed at one end by the cam plate and at the opposite end by the cap flanges to form chambers in the nutating plate. Passageway means are provided from the piston chambers to these plate chambers so that pressurized fluid, usually a lubricating liquid, may also pressurize the chambers in the plate to provide a counterbalancing force to the thrust force which is transmitted from the pistons to the cam plate as the device is in operation.

The above and other related objects and features of the invention will be apparent from a reading of the following description of the disclosure found in the accompanying drawings and the novelty thereof pointed out in the appended claims.

In the drawings:

FIG. 1 is a sectional elevation of a pump embodying the present invention.

FIG. 2 is a section taken on line II-II in FIG. l; and

FIG. 3 is a section taken on line III-III in FIG. l.

FIG. 4 is a perspective view of a modified embodiment of the invention.

The pump seen in FIGS. 1-3 comprises a housing 10 secured to a base piate 12 by screws 14. The base plate 12 has inlet and discharge ports numbered 16 and 18 respectively which in turn are connected to conduits (not shown) for conducting fluids, usually liquids, to and from the pump.

The base of a pump body 20 sealingly engages the upper surface of the plate 12 and overlies the ports 16 and 18. A plurality of cylindrical chambers 22 formed inthe pump body 20 are successively registerable with the ports 16 and 18. A piston 24 is slidably received in each of the chambers 22. Each of the pistons 24 is formed with a ball end 26 which is received by a socket in a cap 28. These sockets are swaged to retain the ball ends 26 therein. The caps 28 bear against the undersurface of a plate 30 which wobbles or nutates relative to the pump body 20.

In the present embodiment the pump body 20 is rotated relative to a xed cam plate 32 to obtain the wobble action referred to. To this end the pump body 20 is joined to the lower end of a shaft 34 by a straight spline connection at 36. Preferably the plate 30 rotates at the same rate as the pump body about the axis of shaft 34 as provided for by the spherical spline connection indicated at 38. The upper end of the shaft 34 is appropriately journaled in the housing 10 and projects therethrough for connection to a rotary power source to be driven in the direction indicated by the arrow.

As the shaft 34 rotates about a vertical axis x, the plate 3@ nutates about a horizontal axis y. The spherical spline connection 38 accommodates this nutating action while maintaining a drive connection between the shaft 34 and the plate 3i) so that relative angular movement, about axis x, between plate 30 and pump body 20 is prevented. It will also be noted that the upper surface of the plate 30 is socketed at 39 to receive the lower portion of the plate 32 to thus laterally position the plate 30 as it nutates.

The nutating or wobble movement of the plate 3i) causes the pistons 30 to reciprocate in the chambers 22 so that as they move upwardly, liquid is drawn from the inlet port 16 and discharged under positive pressure through the discharge port 18. Thus the right hand piston 24 (FIG. 1) will next move downward and exert a bearing load on plates 30, 32 as it discharges liquid from its chamber 22. The left hand piston 24 will move upwardly to draw liquid into its chamber 22. It will be noted that on such a suction stroke there is a tendency for the cap 23 to be drawn yfrom the plate 30. To prevent this, a plurality of clips 41 (FIGS. 1-3) may be secured to the plate 30 by screws 43. These clips form slots 45 which capture the lower portions of the caps to retain them against the plate during a suction stroke.

While the tilt plate 32 is stationary in normal operation, it is also adjustable about an axis normal to and intersecting the axes x and y in order to control lthe volume and capacity of a given pump. The cam plate 32 is mounted on trunnions 49 (indicated in FIG. 1) which are appropriately journaled. Means `(not shown) are then provided to tilt the plate 32 on the trunnions 4t) to and lock it at a desired angle. The upper surface of the plate 32 is cylindrically formed and engages rolls 42 to provide a thrust support for the plate 32 in any position to which it is to be adjusted.`

The spherical ball ends 26 are each generated about respective centers which lie in a common plane z. The sockets in the caps 28 are correspondingly formed to receive the ball ends 26 with a close t permitting esse-ntially free swivelling movement. Next it will be noted that the upper ends of the caps 28 are received by clearance holes 44 in the plate 30. The actual surface on each cap which transmits a thrust load to the plate 30 is an annular flange surface 46 which lies in the plane z, as does the lower bearing surface of the plate 30 which surface is preferably parallel to its opposed upper surface that engages the angled bearing surface of the cam plate 32.

It is to be understood that the forces acting on the caps 28 are relatively complex and involve not only a vertical thrust load but also a horizontal component of this thrust load. Further as the plate 36 nutates, there is relative radial movement (referenced to axis x) between it and the caps 23 as will be evident from FIG. 3. This causes nutation of the caps 28 on the ball ends 26. The coincidence of the centers for the ball ends 26 on plane z is effective in preventing any forces, incident to this compound movement which might cause the caps 28 to tilt relative to the plate 30 and cause a stress concentration. There may be rotation of the caps 28 relative to the ball ends 26 or plate 30, but this tendency is also minimized by the coincident relationship referred to and by the fact that there is no direct contact between the caps 28 and the fixed angle plate 32. The upper surface of the plate 30 transmits the thrust load to the stationary plate 32 and because of its large surface contact therewith there is little or no tendency for relative tipping therebetween.

Not only does the described arrangement provide for the transmission of thrust forces from the rotating and reciprocating pistons 24 to the stationary angle plate 32 in a manner which minimizes stress concentrations and gives optimum wear under a wide range of operating conditions, it enables the provision of countcrbalancing lubrication forces which further minimize wear and the power requirements for operation of the pump.

From the above, it will be appreciated that the flange surfaces 46 sealingly engage the undersurface of the nutating plate 30 and the upper surface of the latter sealingly engages the xed angle plate 32. The ends of the holes 44 are thus sealed to form closed chambers. A bleed hole 4S is formed in the upper end of each piston 24 and opens into a countersink S0 in the upper surface of each ball end 26. A hole 52 in each of the caps 28 is thus able to maintain the chambers in plate 3i) in communication with the piston chambers 22 at all times. The chambers in platepsi) are thus at essentially the same pressure as the piston chambers 22 at all times. The diameter of the holes 44 is preferably somewhat less than that of the chambers 22 so that the effective forces on the caps 28 and plate 32 minimize the thrust forces on the nutating plate 3i) without causing actual separation or excessive leakage therebetween.

Not only does this arrangement minimize wear forces, it also effectively introduces lubricant in those areas where it is required since pumps of this type are frequently used in pressurizing oil or other liquids having lubricating properties.

FIG. 4 illustrates another embodiment of the invention in which an alternate means is employed to rotate a nutating plate 30 simultaneously with the pump body 2t). The shaft 34 and plate 30 have been modified to eliminate the spherical spline connection therebetween as described in the previous embodiment. Further pintles 54 project from opposite sides of the plate 30 and carry journal blocks 56 thereon. These journal blocks are guidingly received in slots 58 formed in a shroud l60, secured to the pump body 20 for rotation therewith. The remaining components of the pump may be as before and those seen in FIG. 4 are identified by like reference characters.

As previously indicated, the described pump may also be used as a motor by the appropriate introduction of pressurized uid into the piston chambers. Also the cam plate 32 may be rotated relative to the pump body 2i) to obtain the desired nutating action. Further, variations, in the constr-uctional details disclosed, will be apparent to those skilled in the art within the broader scope of the present inventive concepts which are to be derived solely from the following claims.

Having thus described the invention, what is claimed as novel and desired to be secured by Letters Patent of the United States is:

1. A pump or the like comprising,

a pump body and a cam plate which are relatively rotatable,

said pump body having a plurality of circularly arranged chambers generally parallel to the axis of relative rotation,

said cam plate having a bearing surface facing said pump body and angled from a plane normal to the axis of relative rotation,

pistons respectively reciprocable in said chambers and projecting from one end thereof towards said cam plate,

said pistons having spherical ball ends,

caps having sockets respectively receiving said ball ends,

said caps further having flanges disposed in a common plane, which plane is coincident with the centers about which the ball ends are generated,

a wobble plate having opposed surfaces, one of which bears against the angled surface of the cam plate and the other of which is relieved to receive the portions of said caps outwardly of said common plane,

the other of the surfaces of said wobble plate providing a bearing surface engaged by the cap flanges on said common plane, and

means preventing relative angular movement between said wobble plate and said piston body about said axis of relative rotation whereby the plate is nutated relative to said piston body, during said relative rotation, as the pistons are reciprocatcd in said chambers, and thrust forces are transmitted between the pistons and cam plate with no tendency to tip the caps relative to said wobble plate.

2. A pump or the Ilike comprising,

apump body and a cam plate which are relatively rotatable,

said pump body having a plurality of circularly arranged cylindrical -chambers concentric of and generally parallel to the axis of relative rotation,

said cam plate having a bearing surface facing said pump body and angled from a plane normal to the axis of relative rotation,

pistons respectively reciprocable in said chambers and projecting from one end thereof toward said cam plate,

inlet and outlet passageways successively communicating with the opposite ends of the piston chambers as relative rotation occurs,

said pistons having spherical ball ends,

caps having sockets respectively receiving said ball ends,

said caps further having anges disposed in a common plane, which plane is coincident with the centers about which the ball ends are generated,

a wobble plate having parallel opposed surfaces one of which bears against the angled bearing surface of the cam plate,

said wobble plate having clearance holes therethrough receiving the portions of said caps outwardly of said common plane,

the other of said parallel surfaces providing a bearing surface engaged by the cap flanges on said common plane, and

means preventing relative -angu'lar movement between said wobble plate and said piston body about said axis of relative rotation whereby the wobble plate is nutated relative to said piston body as relative rotation occurs,

whereby as the pistons are reciprocated in said chambers, thrust forces are transmitted between the pistons and the cam plate with no tendency to tip the caps relative to the wobble plate or the wobble plate re'lative to the cam plate, thereby minimizing stress concentrations between the bearing surfaces carrying such thrust loads.

3. A pump or the like comprising,

a pump body and a cam plate which are relatively rotatable,

said pump body having a plurality of circularly arranged cylindrical chambers concentric of and generally parallel to the axis of relative rotation,

said cam plate having a bearing surface facing said pump body and angled from a plane normal to the axis of relative rotation,

pistons respectively reciprocable in said chambers and projecting from one end thereof toward said cam plate,

inlet and outlet passageways successively communicating with the opposite ends of the piston chambers as relative rotation occurs,

said pistons having spherical ball ends,

caps having sockets respectively receiving said ball ends,

said caps further having uninterrupted anges disposed in a common plane which plane is coincident with the centers about which the ball ends are generated,

a wobble pl-ate having opposed surfaces, one of which sealingly bears against the angled bearing surface of the cam plate,

said wobble plate having clearance holes therethrough receiving the portions of said caps outwardly of said common plane,

the other of said surfaces providing a bearing surface sealingly engaged by the cap anges on said common plane whereby the holes in said wobble plate define chambers,

means p-reventing relatively angular movement between said wobble plate and said piston body about said axis of relative rotation whereby the wobble plate is nutated relative to said piston body as relative rotation occurs,

passageway means through said pistons and said caps, placing the piston chambers in communication with the chambers fonmed in the wobble plate whereby counterbalancing fluid pressures are provided to the thrust forces transmitted between the caps and the cam plate, as pistons are reciprocated in said piston chambers, and thrust forces are transmitted between the pistons and the cam plate with no tendency to tip the caps relative to the wobble plate or the wobble plate relative to the cam plate so that stress concentrations and bearing loads between the wobble plate and cam plate and the caps are maintained at a minimum,

4. A pump or the like comprising,

a pump body and a cam plate which are relatively rotatable,

said pump body having a plurality of circularly arranged cylindrical chambers concentric of and general'ly parallel to the axis of relative rotation,

CII

a plurality of said cam plate having a bearing surface facing said pump body and angled from a plane normal to the axis of relative rotation,

pistons respectively reciprocable in said chambers and projecting from one end thereof toward said cam plate,

inlet and outlet passageways successively communicating with the opposite ends of the piston chambers as relative rotation occurs,

said pistons having spherical ball ends,

caps having sockets respectively receiving said ball ends,

said caps further having uninterrupted flanges disposed in a common plane which plane is coincident with the centers about which the ball ends are generated,

a wobble plate having parallel opposed surfaces, one

of which sealingly bears against the angled bearingy surface of the cam plate,

said wobble plate having clearance holes therethrough receiving the portions of said caps outwardly of said common plane,

the other of said opposed parallel surfaces providing a bearing surface sealingly engaged by the cap flanges on said common plane whereby the holes in said wobble plate 'define chambers,

means preventing rel-atively angular movement between said wobble plate and said piston body about said axis of relative rotation whereby the wobble plate is nutated relative to said body as relative rotation occurs,

said common plane intersecting the axis of relative rotation and said cam plate being pivotally adjustable .about an axis lying in said common plane and normal to the axis of relative rotation,

passageway means through said pistons and said caps, placing the piston chambers in communication with the chambers formed in the wobble plate whereby counterbalancing uid pressures are provided to the thrust forces transmitted between the caps and the cam plate, as pistons are reciprocated in said piston chambers, and thrust forces are transmitted between the pistons and the cam plate with no tendency to tip the caps relative to the wobble plate or the wobble plate relative to the cam plate so that stress concentrations and bearing loads between the wobble plate and cam plate and the caps are maintained at a minimum.

5. A pump or the like comprising,

a pump body having -a plurality of genera'lly parallel chambers therein,

pistons respectively reciprocable in said chambers, projecting from one end thereof and having spherical ball ends,

caps having sockets respectively receiving said ball ends,

said caps further having uninterrupted ange portions disposed in a common plane which plane is coincident with the centers about which the ball ends are generated,

a plate relieved to receive the portions of said caps outwardly of said common plane and having bearing surface portions sealingly engaged by the cap flanges on said common plane to form chambers in said plate,

and means for imparting nutating movement between said plate and said piston body,

and passageway means connecting said plate chambers respectively with said piston chambers so that fluid pressure is created in the plate chambers,

whereby as the pistons are reciprocated in said chambers, thrust forces are transmitted with no tendency to tip the caps relative to said plate and the pressure in said plate chambers provides a counterbalancing force to the thrust forces transmitted between the caps and the plate.

6. A pump or the like comprising a pump body having generally parallel chambers therein,

v'pistons respectively reciprocal in said chambers,

` each of said pistons having a cap spherically mounted on the outer end thereof, each of said caps having ,a ange lying in a plane coincident with the center of the spherical mount therefor,

said plate being relieved to receive the portions of said caps outwardly of said flanges, with said flanges engaging the rst bearing .surface of said plate for the transmission of thrust forces thereto,

an angled thrust transmitting member engaging the second bearing surface of said plate,

means for imparting relative nutating movement between said plate and said casing, and

means for constraining relative movement between said plate and said angled member to rotational movement, said plate and caps `being the sole thrust transmitting members between said angled member and said pistons,

References Cited UNITED STATES PATENTS 2,776,629 1/1957 Keet 103-162 5 2,864,456 12/1958 Bauer 6053 3,050,014 8/1962 Sullivan 103-162 3,073,254 1/1963 Hoover 103-162 3,143,858 8/1964 Roeske 60-53 3,198,130 8/1965 Thoma 10s-162 3,240,159 3/1966 Andrews etal -103-162 l 2,168,658 8/1939 Thomas. 2,555,479 6/1951 Eriksen. 2,880,042 3/1959 Budzich. 3,006,284 10/1961 Pitt et a1.

15 FOREIGN PATENTS 1,269,286 7/1961 France.

Examiners.

R. M. VARGO, Assistant Examiner. 

1. A PUMP OR THE LIKE COMPRISING, A PUMP BODY AND A CAM PLATE WHICH ARE RELATIVELY ROTATABLE, SAID PUMP BODY HAVING A PLURALITY OF CIRCULARLY ARRANGED CHAMBERS GENERALLY PARALLEL TO THE AXIS OF RELATIVE ROTATION, SAID CAM PLATE HAVING A BEARING SURFACE FACING SAID PUMP BODY AND ANGLED FROM A PLANE NORMAL TO THE AXIS OF RELATIVE ROTATION, PISTONS RESPECTIVELY RECIPROCABLE IN SAID CHAMBERS AND PROJECTING FROM ONE END THEREOF TOWARDS SAID CAM PLATE, SAID PISTONS HAVING SPHERICAL BALL ENDS, CAPS HAVING SOCKETS RESPECTIVELY RECEIVING SAID BALL ENDS, SAID CAPS FURTHER HAVING FLANGES DISPOSED IN A COMMON PLANE, WHICH PLANE IS COINCIDENT WITH THE CENTERS ABOUT WHICH THE BALL ENDS ARE GENERATED, A WOBBLE PLATE HAVING OPPOSED SURFACES, ONE OF WHICH BEARS AGAINST THE ANGLED SURFACE OF THE CAM PLATE AND THE OTHER OF WHICH IS RELIEVED TO RECEIVE THE PORTIONS OF SAID CAPS OUTWARDLY OF SAID COMMON PLANE, THE OTHER OF THE SURFACES OF SAID WOBBLE PLATE PROVIDING A BEARING SURFACE ENGAGED BY THE CAP FLANGES ON SAID COMMON PLANE, AND MEANS PREVENTING RELATIVE ANGULAR MOVEMENT BETWEEN SAID WOBBLE PLATE AND SAID PISTON BODY ABOUT SAID AXIS OF RELATIVE ROTATION WHEREBY THE PLATE IS NUTATED RELATIVE TO SAID PISTON BODY, DURING SAID RELATIVE ROTATION, AS THE PISTONS ARE RECIPROCATED IN SAID CHAMBERS, AND THRUST FORCES ARE TRANSMITTED BETWEEN THE PISTONS AND CAM PLATE WITH NO TENDENCY TO TIP THE CAPS RELATIVE TO SAID WOBBLE PLATE. 